Typically, highly crystalline, phase separated thermoplastic polyurethanes have not been utilized in extrusion applications as the compositions are generally difficult to process or even unprocessable as they crystallize and form conglomerates or chunks of solid matter in the extrusion process equipment. Furthermore, attempts to prevent crystallization by increasing the processing temperatures of the extrusion equipment have been unsuccessful and result in heat-decomposed products.
Highly crystalline thermoplastic polyurethane (TPU) products with desirable properties for extrusion have heretofore generally been unavailable. Thermoplastic polyurethanes with high crystallinity have stronger wear resistance and solvent resistance than their relatively low crystalline counterparts.
Highly crystalline thermoplastic polyurethanes also set up faster during extrusion process making the extruded shapes such as hose, tube, sheets, films, fibers and profiles easier to handle after the polymer melt exits the shaping die. This is desirable because it leads to increased productivity and better final product quality.